Enhanced lubricant composition

Abstract

Disclosed herein is a lubricant composition comprising a base oil or a fully formulated lubricant; and graphene nanoparticles derived from a carbon-containing gas dispersed in the base oil or the fully formulated lubricant.

Description

Technical Field

[0001] The present invention relates to enhanced lubricant compositions and methods for forming such lubricant compositions, the enhanced lubricant compositions comprising a base oil having graphene derived from a carbon-containing gas. Background Technology

[0002] Lubricants are important in mechanical devices for reducing wear, for example by reducing friction and wear, improving heat transfer between mechanical parts, reducing corrosion, and providing thermal protection for mechanical parts.

[0003] It is desirable to provide lubricants with enhanced properties, such as increased lubricity and / or coefficient of friction, to provide enhanced protection for mechanical components.

[0004] The purpose of this invention is to address one or more shortcomings of the prior art and / or to provide useful alternatives.

[0005] Any reference to prior art in this specification is not, and should not be construed as, an admission or suggestion of any kind that the prior art constitutes part of the common knowledge of those skilled in the art. Summary of the Invention

[0006] In a first aspect of the invention, a lubricant composition is provided, comprising:

[0007] Base oils or fully formulated lubricants; and

[0008] Graphene nanoparticles derived from carbon-containing gases dispersed in base oils or fully formulated lubricants.

[0009] In a second aspect of the invention, a method for preparing a lubricant composition is provided, comprising: dispersing graphene nanoparticles derived from a carbon-containing gas in a base oil or a fully formulated lubricant.

[0010] In one embodiment, the lubricant composition is a lubricant concentrate. In another embodiment, the lubricant composition is a finished lubricant.

[0011] In this embodiment, the amount of graphene nanoparticles present is about 0.001 wt%. Preferably, the amount of graphene nanoparticles present is about 0.01 wt%. More preferably, the amount of graphene nanoparticles present is about 0.1 wt%. Even more preferably, the amount of graphene nanoparticles present is about 1 wt%. Still more preferably, the amount of graphene nanoparticles present is about 10 wt%.

[0012] In some embodiments, the graphene nanoparticles are present in an amount of up to about 20 wt%. However, in some embodiments, the graphene nanoparticles are present in an amount of up to about 10 wt%, 2 wt%, 1 wt%, or 0.01 wt%. For example, one or more forms of the composition may contain graphene nanoparticles in amounts of: 0.001 wt% to 0.01 wt%, or 0.01 wt% to 1 wt%, or 0.1 wt% to 1 wt%, or 1 wt% to 2 wt%, or 2 wt% to 10 wt%, or 10 wt% to 20 wt%.

[0013] Technicians will understand that the weight ratio of graphene nanoparticles will depend on the intended application, such as whether the lubricant composition is a concentrate or a fully formulated lubricant.

[0014] In the implementation scheme, the graphene is substantially free of metallic and semi-metallic impurities. In one form, the metallic or semi-metallic impurities are selected from the group consisting of: Fe, Co, Cu, Mo, Ni, Si, and their oxides. "Substantially free" means that the total amount of metallic or semi-metallic impurities is less than 1 ppm. Preferably, the total amount of metallic or semi-metallic impurities is less than 1 ppb. Even more preferably, the metallic or semi-metallic impurities are below the detection limit.

[0015] In the embodiments, the lubricant composition is substantially free of graphene oxide and / or reduced graphene oxide. "Substantially free" means that the graphene nanoparticles contain the following amounts of graphene oxide and / or reduced graphene oxide: 1 wt% or less of graphene, preferably 0.1 wt% or less, more preferably 0.01 wt% or less, and most preferably less than the detection limit.

[0016] In the implementation scheme, the graphene nanoparticles have a size of about 2 nm to about 250 nm.

[0017] In the implementation scheme, the graphene nanoparticles comprise platelets or flakes, are substantially composed of platelets or flakes, are composed of platelets or flakes, or are in the form of platelets or flakes.

[0018] In the implementation scheme, the graphene nanoparticles comprise multilayer graphene, are substantially composed of multilayer graphene, are composed of multilayer graphene, or are formed of multilayer graphene.

[0019] In some embodiments, the lubricant composition further comprises a dispersant. However, in other forms, the lubricant composition does not contain a dispersant. In embodiments where a dispersant is present, the amount of the dispersant is preferably from about 0.001 wt% to about 2 wt%.

[0020] In one form of the above-described embodiments, the dispersant is selected from the group consisting of: polyisobutylene succinimide, (2-methoxymethylethoxy)propanol, octadecanoic acid, 12-hydroxy polymers having α-hydro-ω-hydroxy poly(oxy-1,2-ethylenediyl), catalytic reforming fractionation agents, sulfonated polymers with formaldehyde, sodium salts, poly(oxy-1,2-ethylenediyl), α-sulfonyl-w-[2,4,6-tris(1-phenylethyl)phenoxy]-ammonium salts, tristyrylphenol ethoxylates, polyalkylene oxide derivatives of alcohols, propane-1,2-diol, naphtha, base oils and mineral oils, and combinations thereof.

[0021] In an implementation of the second aspect, the method includes providing graphene nanoparticles derived from a carbon-containing gas.

[0022] In one embodiment of the second aspect, the step of dispersing graphene nanoparticles includes:

[0023] A mixture that forms graphene nanoparticles in a base oil or fully formulated lubricant; and

[0024] The mixture is subjected to high-shear mixing.

[0025] In one embodiment of the above-described scheme, high-shear mixing occurs at approximately 40,000 to approximately 60,000 s. -1 The shearing rate was [value].

[0026] In one embodiment of the above implementation, the step of subjecting the mixture to high shear mixing is carried out for about 5 minutes to about 72 hours.

[0027] In a second embodiment, the method further includes adding a dispersant to the mixture.

[0028] In a second embodiment, the method further includes producing graphene nanoparticles from a carbon-containing gas.

[0029] In a third aspect of the invention, a lubricant composition formed by the method according to the second aspect of the invention is provided, and / or embodiments thereof and / or forms thereof.

[0030] In a fourth aspect of the invention, use is provided for a lubricant composition, and / or embodiments thereof, and / or forms thereof, according to the first or third aspect of the invention, as a lubricant concentrate or finished lubricant.

[0031] Within the scope of this invention, any feature described herein may be combined with any one or more other features described herein to form any combination.

[0032] Preferred features, embodiments, and variations of the present invention can be derived from the following detailed description, which provides those skilled in the art with sufficient information to practice the invention. This detailed description should not be construed as limiting the scope of the foregoing in any way.

[0033] Detailed description

[0034] This invention relates to a lubricant composition and a method for forming such a lubricant composition, the lubricant composition comprising a base oil or a fully formulated lubricant, wherein graphene derived from a carbon-containing gas is dispersed in the base oil or fully formulated lubricant. The inventors have discovered that using graphene derived from a carbon-containing gas enables the graphene to be dispersed in the base oil or fully formulated lubricant for a longer period and in a better manner compared to graphene prepared in other ways (e.g., graphene derived from graphite).

[0035] The inventors have discovered that the lubricant compositions of the present invention exhibit one or more improved wear protection, heat transfer, mechanical thermal protection, and reduced corrosion of mechanical parts.

[0036] Graphene derived from carbon-containing gases differs from graphene produced from graphite. Typical methods for producing graphene from graphite include physical processes (such as micromechanical exfoliation of graphite) or chemical processes (such as the modified Hummer method).

[0037] Graphene exfoliation produces graphene by detaching graphene layers from graphite. One problem with this method is that the resulting graphene contains any impurities present in the parent graphite, including Fe, Co, Cu, Mo, Ni, and Si (and their oxides). The presence of these impurities in lubricant compositions is undesirable because they have a detrimental effect on the dispersion of graphene in the base oil and the final function of the lubricant composition, and in some cases may be harmful to mechanical operation and metal parts.

[0038] The modified Hummer method involves chemically oxidizing graphite to graphene oxide (GO). The graphene oxide can then be chemically reduced to reduced graphene oxide (rGO). In short, the method involves treating graphite with an oxidizing solution to convert it into graphene oxide; this oxidizing solution may include, for example, potassium permanganate, sulfuric acid, and hydrogen peroxide. Graphene oxide contains oxidized functional groups, such as hydroxyl, epoxy, and carboxyl groups. The graphene oxide can then be reduced to rGO using methods known to those skilled in the art, such as chemical, thermal, or electrochemical methods. While this reduction process is suitable for reducing the overall density of oxidized functional groups, the resulting rGO still contains oxidized functional groups. The presence of graphene oxide, reduced graphene oxide, or these oxidized functional groups in a lubricant composition is undesirable because they have a detrimental effect on the dispersion of graphene in the base oil and the final function of the lubricant composition, and in some cases may be harmful to mechanical operation and metal parts.

[0039] Furthermore, using various chemical reagents to promote the conversion of graphite into graphene / GO / rGO will also introduce chemical impurities into the resulting graphene / GO / rGO, which is undesirable in lubricant compositions, as these also have a detrimental effect on the lubricant, for reasons mentioned above.

[0040] Besides impurity issues, these methods typically result in almost no control over the final size of the resulting graphene / GO / rGO in terms of particle size and layer thickness, and are usually in the form of multilayer graphene / GO / rGO with a wide range of particle sizes.

[0041] In contrast, graphene derived from carbon-containing gases has high purity. The absence of these impurities avoids their potentially detrimental effects on the lubricant composition.

[0042] The lubricant composition can be formed by forming a base oil (which may be, for example, one or more mineral base oils, semi-synthetic base oils, fully synthetic base oils, or mixtures thereof, or known Group 1, Group 2, Group 3, Group 4, or Group 5 base oils) or a fully formulated lubricant mixture with graphene. The amount of graphene is typically 0.001 wt% to 0.01 wt%, or 0.01 wt% to 1 wt%, or 0.1 wt% to 1 wt%, or 1 wt% to 2 wt%, or 2 wt% to 10 wt%, or 10 wt% to 20 wt%, depending on the intended application. Graphene is typically in the form of graphene nanoparticles with a size ranging from about 2 nm to at most about 250 nm and exhibiting a flake or sheet-like morphology.

[0043] Generally, if a lubricant concentrate is required, graphene can be present in the following amounts: 0.001 wt% to 0.01%, 0.01 wt% to 1%, 0.1 wt% to 1 wt%, 1 wt% to 2 wt%, 2 wt% to 10 wt%, and 10 wt% to 20 wt%. In this case, the lubricant concentrate can be stored for a period of time before dilution to form the finished lubricant. Due to the high concentration of graphene and the potential for storage of the lubricant concentrate before use, the dispersibility of graphene in the base oil is important. The advantage of graphene derived from carbon-containing gases is that, due to its high purity, for a given weight fraction, the lubricant composition has a higher graphene particle loading than graphene derived from lower purity sources. For example, graphene derived from carbon-containing gases can be used in amounts potentially up to 100 times greater than other graphene sources to achieve the same or higher particle loading, which contributes to improved performance of the lubricant composition.

[0044] Lubricant concentrates can be diluted with one or more base oils to form finished lubricants, wherein the base oils may be the same as or different from the base oils of the lubricant concentrates.

[0045] Alternatively, if a finished lubricant is required, graphene may be present in amounts of 0.001 wt% to 0.01%, 0.01 wt% to 1%, 0.01 wt% to 1%, 1 wt% to 2 wt%, 2 wt% to 10 wt%, or 10 wt% to 20 wt%.

[0046] In either case, graphene is added to the base oil and subjected to high-shear mixing to suspend the graphene in the base oil. The inventors have discovered that, at least 40,000 seconds... -1 Mixing at high shear rates is beneficial for dispersing graphene in base oils. High-shear mixing can take from approximately 5 minutes to approximately 72 hours, depending on the properties of the graphene, the type of base oil, and the presence of additives.

[0047] Dispersants can also be used to increase the stability or uniformity of dispersions and extend the shelf life of products. If a dispersant is used, it is typically added in amounts from about 0.001 wt% to about 2 wt%. A range of suitable dispersants can be used, such as ionic and nonionic surfactants, polymers, copolymers, and mixtures thereof. Suitable dispersants include: polyisobutylene succinimide, (2-methoxymethylethoxy)propanol, octadecanoic acid, 12-hydroxy polymers with α-hydro-ω-hydroxy poly(oxy-1,2-ethylenediyl), catalytic reforming fractionation agents, sulfonated polymers with formaldehyde, sodium salts, poly(oxy-1,2-ethylenediyl), α-sulfonyl-w-[2,4,6-tris(1-phenylethyl)phenoxy]-ammonium salts, tristyrylphenol ethoxylates, polyalkylene oxide derivatives of alcohols, propane-1,2-diol, naphtha, or commercially available dispersants such as DYSPERBYK 194N, DYSPERBYK 192, DYSPERBYK 199, DYSPERBYK 2013, DYSPERBYK 2015, Triton X-100, Brij L23, BrijO10, Ecoteric T20, Hydrapol RP40, Hydrapol RP90, Tersperse 2020, Tersperse 2218, Tersperse 2218, Tersperse 2288, Tersperse 2500, Tersperse 2510, and combinations thereof.

[0048] Example 1

[0049] Lubricant concentrates are prepared by mixing mineral base oils, semi-synthetic base oils, and fully synthetic base oils with graphene derived from carbon-containing gas using a high-shear mixer. The wt% of the graphene derived from carbon-containing gas ranges as follows: 0.001 wt% to 0.01 wt%, 0.01 wt% to 1 wt%, 0.01 wt% to 1 wt%, 1 wt% to 2 wt%, 2 wt% to 10 wt%, and 10 wt% to 20 wt%. The lubricant concentrates are then diluted to a final graphene concentration of 0.001 wt% to 0.01%, 0.01 wt% to 1%, 0.01 wt% to 1%, 1 wt% to 2 wt%, 2 wt% to 10 wt%, and 10 wt% to 20 wt% in the finished lubricant, depending on the initial concentration and the final desired concentration.

[0050] The finished lubricant was then subjected to a modified ASTM 4 ball wear test, and the results were compared with those of the same single base oil or fully formulated lubricant without graphene. The results are shown in Table 1 below:

[0051] Table 1: Improved ASTM Test Results

[0052] Improved ASTM D2783 Extreme pressure test of lubricating fluid Increase by up to 5% Improved ASTM D4172 Lubricant anti-wear test Increase by up to 20%

[0053] Example 2

[0054] This embodiment reports experimental results obtained by mixing Group 3 and Group 4 base oils with 0.01 wt% graphene in the absence of a dispersant using a high-shear mixer.

[0055] Graphene is a multilayer graphene with a particle size ranging from 2 to 250 nm.

[0056] Table 2 below shows that the addition of graphene significantly improved the COF (coefficient of friction) of the base oils in groups 3 and 4.

[0057] Table 2: Results showing improved COF of Group 3 base oils

[0058]

[0059] Example 3

[0060] This embodiment reports experimental results obtained by mixing commercially available Shell oil with 0.01 wt% graphene in the presence of a dispersant using a high-shear mixer.

[0061] Graphene is a multilayer graphene with a particle size ranging from 2 to 250 nm.

[0062] Table 3 below illustrates that the addition of graphene significantly improves the COF (coefficient of friction) of Shell commercially available oils.

[0063] Table 3: Results showing improved COF of Shell commercially available oils

[0064]

[0065] The experiment was repeated using a series of dispersants, including: polyisobutylene succinimide, (2-methoxymethylethoxy)propanol, octadecanoic acid, 12-hydroxy polymers with α-hydro-ω-hydroxy poly(oxy-1,2-ethylenediyl), catalytic reforming fractionation agents, sulfonated polymers with formaldehyde, sodium salts, poly(oxy-1,2-ethylenediyl), α-sulfonyl-w-[2,4,6-tris(1-phenylethyl)phenoxy]-ammonium salts, tristyrylphenol ethoxylates, polyalkylene oxide derivatives of alcohols, and propane-1,2-diol. In each case, similar results were obtained.

[0066] Those skilled in the art will understand that many embodiments and modifications can be made without departing from the scope of the invention. Throughout the specification, references to "one embodiment" or "implementation" mean that a particular feature, structure, or characteristic described in connection with an embodiment is included in at least one embodiment of the invention. Therefore, the phrases "in one embodiment" or "in an embodiment" appearing in different places throughout the specification do not necessarily refer to the same embodiment. Furthermore, particular features, structures, or characteristics can be combined in one or more combinations in any suitable manner.

Claims

1. A lubricant composition comprising: Base oils or fully formulated lubricants; Dispersants; and Graphene nanoparticles derived from carbon-containing gases dispersed in the base oil or the fully formulated lubricant; And the graphene nanoparticles are present at a concentration of 0.001 wt% to 0.01 wt% of the total weight of the lubricant composition, and The lubricant composition is substantially free of graphene oxide and / or reduced graphene oxide, wherein substantially free of graphene means that the graphene nanoparticles contain 1 wt% or less of graphene oxide and / or reduced graphene oxide.

2. The lubricant composition of claim 1, wherein the lubricant composition is formed by dispersing the graphene nanoparticles in the base oil or fully formulated lubricant through high-shear mixing.

3. The lubricant composition of claim 1, wherein the graphene nanoparticles are substantially free of metallic and semi-metallic impurities selected from the group consisting of Fe, Co, Cu, Mo, Ni, Si and their oxides, wherein substantially free means that the total amount of metallic or semi-metallic impurities is less than 1 ppm.

4. The lubricant composition of claim 1, wherein the graphene nanoparticles have a size of 2 nm to 250 nm.

5. The lubricant composition of claim 1, wherein the graphene nanoparticles are in the form of sheets.

6. The lubricant composition of claim 1, wherein the graphene nanoparticles are in the form of sheets.

7. The lubricant composition of claim 1, wherein the graphene nanoparticles are formed from multiple layers of graphene.

8. The lubricant composition of claim 1, wherein the graphene nanoparticles are composed of multiple layers of graphene.

9. The lubricant composition of claim 1, wherein the dispersant is present in an amount of 0.05 wt% to 2 wt%.

10. The lubricant composition of claim 1, wherein the dispersant is selected from the group consisting of: polyisobutylene succinimide; (2-methoxymethylethoxy)propanol; octadecanoic acid; 12-hydroxy polymers having α-hydro-ω-hydroxy poly(oxy-1,2-ethylenediyl); catalytic reforming fractionation agents, sulfonated polymers with formaldehyde, sodium salts; poly(oxy-1,2-ethylenediyl), α-sulfonyl-w-[2,4,6-tris(1-phenylethyl)phenoxy]-ammonium salts; tristyrylphenol ethoxylates; polyalkylene oxide derivatives of alcohols; propane-1,2-diol; and combinations thereof.

11. A method for preparing a lubricant composition, the method comprising: Graphene nanoparticles derived from carbon-containing gases are dispersed in a base oil or a fully formulated lubricant, wherein the graphene nanoparticles are present at a concentration of 0.001 wt% to 0.01 wt% of the total weight of the lubricant composition, and wherein the lubricant composition is substantially free of graphene oxide and / or reduced graphene oxide, wherein substantially free of graphene means that the graphene nanoparticles contain 1 wt% or less of graphene oxide and / or reduced graphene oxide. The step of dispersing the graphene nanoparticles includes: A mixture of graphene nanoparticles formed in the base oil or the fully formulated lubricant; The mixture is subjected to high shear mixing; and Add a dispersant to the mixture.

12. The method of claim 11, wherein the method includes providing graphene nanoparticles derived from a carbon-containing gas.

13. The method of claim 11, wherein the high-shear mixing occurs at 40,000 to 60,000 s. -1 The shearing rate was [value].

14. The method of claim 11, wherein the step of subjecting the mixture to high-shear mixing is carried out for a period of 5 minutes to 72 hours.

15. The method of claim 11, wherein the method further comprises generating graphene nanoparticles from a carbon-containing gas.

16. A lubricant composition formed by the method according to any one of claims 11 to 15.

17. Use of the lubricant composition according to any one of claims 1 to 10 as a concentrated lubricant or a finished lubricant.

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